Paperboard printing plate and process of making same



Nov. 30, 1937. J. s. ROYSE ET AL 2,100,358

PAPERBOARD PRINTING PLATE AND PROCESS OF MAKING.SAME

Filed Oct. 28, 1935 INVENTORS.

J/IMES 5, Fol 5E. PHI/1. k. TUANEE.

ATTORNEY 5 Patented Nov. 30, 1937 i UNITED STATES PATENT PAPERBOARDPRINTING PLATE AND PROC- ESS OF MAKING SAME James S. Royse and Paul R.Turner, Terre Haute, Ind., assignol's to Thomson Symon Co., Terre Haute,Ind., a corporation Application october 28, 1925, Serial No. 46,971

12 Claims. (c1.1o1 4o1.1)

This invention relates to the process of forming areas of the pap beardPrinting P t e ea printing plate and the printing plate resulting movedfrom the Supporting a from said process. It has also been determinedthat to obtain a The chief object of the invention is to form a pePrinting Surface Which does not mar 5 printing plate of paper board harat become rapidly unprintable after few impressions 5 In the printing,for example, of billboard posthave been taken therefrom, it is highlydesirable ing copy, the original standard sizes w 24 to seal the minutepores in the exposed ink-resheets each of which was approximately 28" byceiving face of the P p b0a1din Other Words. 42", although recently thisentire copy for a billto an f this printing surface from poss board hasbeen reduced in sheet number and ink s r i ha a t a th u h very sli ht.to 10 creased in the size of sheet, to wit, ten sheets apalmostnon-absorbing Character; proximately 43 by 60%". Th each h t Thistransformation is frequently necessary is of relatively large area andthe material itself, and pa t l y so for large long s u e used inprinting plates heretofore, for printing printing ink is t cky a d ifthe P e Printing such sheets, has been a material item of cost. face isbut slightly porous, the ink i d t e 15 The chief feature of thisinvention consists in Will gradually u h rep at d s ti p rat thereduction of that cost Without destroying the result in marring of theplate p t n surface so length of life of the printing plate resultingthat the resultant co w en printed, will not therefrom and withoutforming from the plate a have that uniformity and depth of Color d 2commercially unsatisfactory sheet of bill board sharpness of outlinewhich is characteristic of 0 copy. metal printing plate production. Thissealing Of course, the invention can b applied t bonds the surfacefibres together so the surface smaller sizes, although the total savingsare not resists suction deformationas large in the aggregate The presentinvention, however, produces a Plates produced by this process have atthe plate'which will produce Y comparable to that 5 present time beencommercially utilized in runs producedholn metal Printing P It, ofexceedin 1,100 impressions per plate this being 4 course, is understoodthat metal printing plates, the largest commercial order upon which theinparticularly of large Size hereihhefore specified, vention has beenutilized to date, the same proare of Shh/able mum-Ply Wood baseducingone sheet of copy for approximately 1,000 to which is secured the metalface, usually of billboards, the extra 100 being the customary sheetZinc, upon which is formed relief the overrun to compensate for spoilagein the running Printing portions and the comparahve P and boardapplication of t posters tween paper board and the metal, result ng in aThe process port-ion of the invention consists marked Saving will beself'evidehtin the utilization of a suitable base of billboard A thinsolution ofiwhlte transfer lacquer not 35 sheet size or the desired sizeand to the same is only provides the Surface Seal fibre bond secured a,composite paper board structure result the plate printing surface butprovides a surface ing in a composite plate for subsequent printingwhich more less Sensitive to the lead when t impression is form dtherein. (graphite and the like) of an ordinary lead pencil 40 It hasbeen determined that best results;and by m that the original of the copym be la'ld out 40 the same is meant the finished sheet of copy for on asheet and by rubbing pressure on pasting on the billboard, is obtainedwhen the the copy applied to the lacquered faice g g paper board portionof the plate is resiliently and there results the transfer of sumc en eamm the copy to the plate printing face to permit the 5 adhesivelysecured. to the supportmg base The workmen to follow the transferredcopy lines and paper board portion of the plate includes two cut throughthe two layers of paper board to retypes Paper board one h hard and themove from the plate the portions which are to be other still harder andof a smoother and higher left blank cori'espondingto the portions whichare calendered finish, the two being adhesively set t b printed by t l tnthe final paper o cured together preferably with a resilient union.'copy,

Also, since the paper board portion of the plate It has been found thatin order to secure the is of multi-lay-er character, preferably thefirst best results in the final copy and since copy subtWO yers aresecured tog throughout their stantially identical to that obtained frommetal entire adjacent faces. When but two layers are plates is desired,due to the lack of rigidity and utilized, substantially all of thenon-printing toughness of a. paper printin rfa as u tinguished from ametal printing surface, some cushioning or yielding effect should beprovided and preferably this is obtained in the adhesive connectionbetween the layers of paper board plate structure and between thecomposite paper board plate structure and the multi ply base structure.This type of connection also compensates for any irregularities in thethickness of the several pieces of paper board utilized. Usually, theresultant board is type high for mounting upon the bed of a cylinderpress. such as a 6-0 fiat bed cylinder Miehle press.

The formation of the printing impression on the plate is made by sharptools cutting through the multl-ply paper board stock to the multiplywood base and following removal of the portions so cut out, the printingsurface remaining has removed therefrom the surplus lacquer or at leastthat portion which is not utilized in sealing the minute pores andbonding the surface fibres together and also if, as and when desired,all cement on the wood board base exposed by the removal of the paperboard portions may be removed. The impression intended, therefore,stands out in relief and will print when inked, copy substantially ofthe same character as printed by a metal plate.

No claim, however, is made that the life of a paper board plate of thischaracter is equal to that of a metal printing plate of equal printingcharacter but it is asserted that for fairly large runs, a paper boardprinting plate is equally as satisfactory as a metal printing plate andmuch cheaper to produce.

Heretofore in the industry, in order to reduce the cost of these largemetal plates, 9. rubber mat surface instead of a metal mat surface hasbeen utilized and it has been determined that a paper board plate of thepresent invention has a length of life sufiicient for the usualrequirements for which a rubber mat is utilized. In one size, thepresent cost of a rubber mat plate is about $8.50, whereas, the presentcost of the present invention. (paper board printing plate) is only$1.25 or there results a saving in plate fabrication of $7.25 per plate.If these comparative costs apply to the largest size plates mentionedfor the ten plates necessary to produce a one-color complete copy for abillboard, there is a saving in plate cost of stood by those engaged inthe printing industry, there will be an additional saving in plate costin the same proportion as to the number of plates required for thereproduction. I

Having now described in some detail the process of preparing a printingpaper board plate, reference will now be had to the plate per se and indescribing the same, further reference will be had to the process ofpreparing or forming it.

The full nature of the invention will be understood from theaccompanying drawing and the following description and claims:- I In thedrawing, Fig. 1 is a plan view of a printing paper board plate, the lefthand portion having the printing face thereon in relief formation andthe right hand portion illustrating the paper printing plate preliminaryto the formation of the printing impression therein.

Fig. 2 is an enlarged sectional view taken on line 2-2 of Fig. 1, and inthe direction of the arrows and substantially of a plate in the stageprior to final completion.

$72.50, and as will be well undera aioasse 3-3 of Fig. 1 and illustratesthe printing plate in its final or completed form.

In the drawing, l0 indicates a suitable base. herein illustrated as offive ply wood stock. The numeral ll indicates a layer of adhesive whichsecures to the base the main body portion of the stock l2 in turnsecured on its opposite face by the layer of adhesive iii to the linerIt.

It has been determined that a suitable liner or facing sheet is one thatmay be designated as .020 red press board and that the main body of thepaper portion of the printing plate may be what is known as point newsboard. The press board is what may also be termed a relatively heavyfibre board having a very hard surface. It is almost the thickness ofcard board. The news board is slightly less than in thickness.

The preferred method of assembling the plate structure is to coat oneside of the 80 point news board with rubber cement and at the same timecoat one side of the .020 red press board. These two coated surfaces arethen allowed to dry naturally or may be dried more rapidly by forceddrying. The cement coated sides of these two boards are then pressedtogether and this forms what may be termed the surface plate" andcorresponds to the metal mat on the plate in the printing industry.

The base i0 is approximately A" thick and the unlined or unsurfaced faceof the surface plate and one face of the base,-each is similarly coatedwith rubber cement,-is permitted to dry until the respective coatedsurfaces become tacky, and then are secured together by a pressurearrangement. In the drawing, the cement layers H and i3 areintentionally represented as slight- 1y thicker compared with referenceto the liner or facing sheet M, the paper body l2 and the base it.

After the entire plate structure has been built up, as aforesaid, theimpressions, as previously set forth, may be formed in relief thereon bycutting away the liner and body portion down to the base iii. This willform a printing plate of satisfactory printing capacity having referenceto a fairly convenient number of printing impressions or printingworkmanship equivalent to a metal plate. However, for a relatively largenumber of impressions and to insure perfect printing, it is preferred toseal or bond the surface of the liner or facing sheet. There is,therefore, applied to the exposed face of the liner a thin solution oflacquer. This seals all imperfections in the exposed liner or surfacesheet and bonds the surface fibres together. This lacquer may be sprayedor brushed thereon. Greater uniformity, however, is obtained by thespraying application.

To facilitate the formation of the printing impression on the printingplate, instead of using a colorless lacquer, there is utilized a whitelacquer. This is known as white transfer lacquer and it is more or lesssensitive to an ordinary lead pencil. The transfer of the desired designto the printing plate is made by merely turning the design in its normalrelation, which has been made by pencil on ordinary litho-paper, facedown on to the lacquer coating and then transferring the lead lines or apart of the lead of the lines on the lithopaper 'to the printing plateand particularly to the white lacquer surface thereof by rubbing. Thisrubbing leaves a sufficient representation of the desired design inreversed relation on the white lacquer surface.

printing surface of the Any omissions in the design may be filled in bypencil, if necessary, and then the plate is cut by hand or by tools, asdesired, and usually the cuts are carried through to the base In andpreferably the cuts are inclined to the plane of the base as shown.After cutting through to the plane of the bwe, the parts of the printingplate which are not to print in the final plate, are removed from thebase which thus leaves the intended impression or printing portion ofthe plate standing out in relief from the base l0.

After the plate has been completely out, all surplus lacquer on theliner face or facing sheet is suitably removed by the use of any desiredlacquer solvent. Of course, the solvent does not remove that portion ofthe lacquer which seals the imperfections or adheres to the surfacefibres for bonding thereof. It merely removes the excess surface coatingIt might be stated these imperfections' are extremely minute incharacter and usually are not visible to the eye, although they may inthe long run due to ink suction action, if not eliminated as set forth,result in poor print ing in the latter portion of the longer run. Thecement which adheres to the base following the removal of the cutoutportions of the paper board portion of the printing plate is thensuitably removed in any desired manner, leaving the exposed portion ofthe base l0 clear or relatively free from cement.

It may be questioned as to why a single thickness of paper board mightnot be utilized in the same manner that a single sheet of rubber ormetal is utilized and in answering the same, it is pointed out that asingle thickness of board, if of the news board type, does not have ahard enough surface and if of the press board type, is possibly toohard. Likewise, the addition of a cushion adhesive connection betweenthe two compensates for irregularities therebetween.

News board stock as an exposed printing face, is not satisfactorybecause of the tackiness of the ink and a rough surface in the boardprinting face results after a relatively few impressions due to such inksuction, which in turn results in poor printing. It has been tried andthe most satisfactory impressions have been only about fifty in number.

Also, it may be stated'that other types of board, heavier and lighterthan 80 point news board, have been utilized with better results thanjust plain news board. However, it has been found that press board whichhas a high calendered finish and is relatively hard and built up toapproximately 80 point, is the most satisfactory for use in theformation of a printing paper plate that will produce printingsubstantially equalin character to that obtained from metal plates.

It might also be stated the foregoing description has been directed to aprinting plate, that is,

what is known as type high, in total thickness, although for purposeswhere such a height is not desired, the thickness of the plate may bevaried accordingly.

It might also be added that the utilization of an imperfectionpreventing sealing medium prevents peeling of the liner for the linerface or surface will, after a considerable run, start to peel at itsweakest pointthe imperfection-edge to the suction and tackiness of theink in its repeated application to the plate and its repeated transferto the paper to be printed.

In the drawing, [5 indicates the white transfer lacquer and the dot 16in Fig. 2 represents the pencil transfer legending that has been rubbedon to the lacquer from the litho-sheet bearing the original design. I1indicates the tapered or inclined cut and the surface l8 indicates thesealed printing surface of the printing paper plate.

The use of the lithe-paper with the lead im pression thereon and thesubsequent transfer by rubbing of the lead lines upon the lacquer, itwill be obvious, results in a mere surface addition and all of thecorrections may be made previously in the copyon the lithopaper and nocorrections will be subsequently required on the plate. Also, instead oftracing through a copy made in reverse form, thecopy is made in itsoriginal form and reversely applied. A better visualization of thecompleted copy may thus be obtained by this method. This methodfurthermore has the additional and more important advantage that theprinting surface is not mutilated in the copy transferring step so thatonly the cutting tool need engage this surface and form the sharplydefined edge, leaving in relief the printing surface withoutimperfections or irregularities in either the surface or the edgeimmediately adjacent thereto, which might result if a stylus were used.

While the invention has been describedin great detail in the foregoingdescription, the same is to be considered as illustrative, notrestrictive in character, and as has been pointed out hereinbefore,various modifications of the invention, both in the product and thearticle, have been set forth, and these as well as others which willreadily suggest themselves to persons skilled in this art, areconsidered to be within the broad scope of this invention, referencebeing had to the appended claims.

The invention claimed is:-

1. A printing plate including a supporting base and a printing body, thelatter comprising a rela tively dense liner of paper board stock, and ofbut slight thickness, and a relatively thicker main portion of paperboard stock secured at opposite faces to the liner and the base.

2. A printing plate including a supporting base and a printing body, thelatter comprising a relatively dense liner of paper board stock, and ofbut 4. A device as defined by claim 1, characterizedby the main portionbeing approximately 80 point 3 news board.

5. A device as defined by claim 2,'characterized by each elasticadhesive connection consisting of rubber cement.

6. A device as defined by claim 1, characterized by the addition of afiller to the exposed face of the liner.

7. A device as defined by claim 1, characterized by the addition of afiller to the exposed face of the liner, said filler comprising a thinsolution or white transfer lacquer permitting pencil copy transferenceand the major portion of which is readily removed following platecutting.

8. The process of preparing a printing plate from paper board, includingresiliently securing a facing sheet to a paper board body, resilientlysecuring the body to a suporting base, sealing the imperfection in andbonding the exposed fibrous surface of the sheet. and cutting in reliefthe i desired impression in both sheet and body preliminary to formingthe printing impression.

9. The process of preparing a printing plate from paper board, includingresiliently securing a paper board facing sheet to a paper board body,resiliently securing the body to a supporting base, sealing theimperfection in and bonding the exposed fibrous surface of the facingsheet with a copy-receiving medium, and applying the desired copythereto preliminary to forming the printing impression therein.

10., The process of preparing a printing plate from paper board,including resiliently securing a facing sheet to a paper board body,resiliently securing the body to a-supporting base, applying to theexposed face of the facing sheet a copy receiving-medium, applying thedesired copy thereto preliminary to forming the printing impressiontherein, and removing all surplus medium subsequent to impressionformation and preliminary to printing therefrom.

11. The process of preparing a printing plate aioasce from paper board,including resiliently securing a paper board facing sheet to a paperboard body, resiliently securing the body to a supporting base, sealingthe imperfections in and bonding the exposed fibrous surface of thefacing sheet with a copy-receiving medium, applying the desired copythereto preliminary to forming the printing impression therein, andremoving all surplus medium subsequent to impression formation andpreliminary to printing therefrom.

12. The process of preparing a printing plate of paper, includingforming a composite paper board plate structure on a supporting base,the structure including an outer facing sheet of paper board and anintermediate body of paper board, sealing the imperfections in andbonding the fibrous inkreceiving surface of the sheet, and cutting theprinting impression therein prior to printing therefrom, the printingimpression being in relief.

JAMES S. 'ROYSE. PAUL R. TURNER.

